Is Marlborough Water Works water safe to drink?

Marlborough Water Works (PWS ID: NH1481010) has 245 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. EPA SDWIS lists this system's service population as 750 people using Groundwater sources.

How many people does Marlborough Water Works serve?

EPA SDWIS reports that Marlborough Water Works serves 750 people (this public water system's service population, not the municipal population of Marlborough or any other city). It is a Local-owned system using Groundwater water sources with 300 service connections. The operator address is listed in Marlborough, New Hampshire.

What type of violations does Marlborough Water Works have?

Marlborough Water Works has 245 total violations: 18 health-based violations (MCL exceedances or treatment failures), 223 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Marlborough Water Works water?

No PFAS testing data is available for Marlborough Water Works under the EPA's UCMR5 monitoring program.

What water source does Marlborough Water Works use?

Marlborough Water Works uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.

Where does this data come from?

All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

Where does Marlborough Water Works sit among U.S. public water systems?

According to EPA SDWIS population_served among sitemap-advertised systems (serving 500+), Marlborough Water Works ranks #23,448 of 29,740 by people served, and #176 of 284 in New Hampshire. Ordinals use population_served DESC among systems serving 500+ (the sitemap cohort). See /methodology#corpus-placement.

How does Marlborough Water Works's violation count compare nationally?

Marlborough Water Works has 245 recorded EPA SDWIS violations, fewer than 12% of the 29,740 public water systems serving 500 or more people nationwide (the same sitemap cohort used for the corpus-placement ranking above). 88% of that cohort has fewer violations than Marlborough Water Works. A system can have zero recorded violations and still be actively monitored, and a high violation count often reflects a system that reports thoroughly, not necessarily one with worse water.

States → New Hampshire

Community Water System · PWS NH1481010

Marlborough Water Works

Operator location Marlborough, New Hampshire - smaller served population (≤ 999) at 750 people served; 245 SDWIS violations on record from groundwater sources.

Compiled by PlainWater · May 15, 2026

750
People served (this PWS) Smaller third of systems: 245
EPA violations (this PWS) Upper third of systems: 18
Health-based (this PWS) Middle third by health-based share: Untested
UCMR5 (this PWS) No UCMR5 result

Follow published updates (RSS)

Marlborough Water Works standing, high SDWIS violation third

750 people served (SDWIS) - smaller served population (≤ 999). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 7% is middle-third health share (≤ 23%). Population rank #23,448 of 29,740 among systems serving 500+.

The verdict

Marlborough Water Works sits in the upper third of the sitemap cohort by violation count (245), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is smaller (750; smaller served population (≤ 999)), so each violation row represents a compact service footprint. Health-based share is 7% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.

#23,448 of 29,740
Population · /systems: #176 of 284
Population · NH: 245
Total EPA violations on record: 7%
Health-based (MCL / treatment failure)

Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.

Water Safety Score

9/100

Marlborough Water Works

Based on EPA SDWIS violation history and UCMR5 PFAS testing only, not water taste, odor, infrastructure age, or contaminants outside the federally tracked set.

Health-based violations F

EPA SDWIS health-based violations on record (MCL, MRDL, treatment technique)

Monitoring & reporting violations F

227

Non-health SDWIS violations (monitoring, reporting, and other compliance)

PFAS contamination N/A

Not UCMR5-tested

Highest PFAS compound level detected in UCMR5 testing

System Details

System Type: Community
Owner Type: Local
Connections: 300
County: Cheshire
School/Daycare: No
MCL Violations: 18
Monitoring Violations: 223
Treatment Tech Violations: 0

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Coliform (TCR)	MCL	18	2010
Coliform (TCR)	MR	13	1993
1,2,4-Trichlorobenzene	MR	10	1995
cis-1,2-Dichloroethylene	MR	10	1995
Xylenes, Total	MR	10	1995
DICHLOROMETHANE	MR	10	1995
o-Dichlorobenzene	MR	10	1995
Vinyl chloride	MR	10	1995
1,1-Dichloroethylene	MR	10	1995
trans-1,2-Dichloroethylene	MR	10	1995
1,2-Dichloroethane	MR	10	1995
1,1,1-Trichloroethane	MR	10	1995
Carbon tetrachloride	MR	10	1995
1,2-Dichloropropane	MR	10	1995
1,1,2-Trichloroethane	MR	10	1995
Tetrachloroethylene	MR	10	1995
CHLOROBENZENE	MR	10	1995
Benzene	MR	10	1995
Toluene	MR	10	1995
Ethylbenzene	MR	10	1995
Styrene	MR	10	1995
p-Dichlorobenzene	MR	10	1995
Trichloroethylene	MR	10	1995
Consumer Confidence Rule	Other	2	2010

Violation Count vs. the National Corpus

Marlborough Water Works has 245 recorded EPA violations, 88% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 12% carry more. 7% of this system's own violations are health-based (18 of 245), and it ranks #23,448 of 29,740 by population served among that same cohort.

EPA violations vs. the national water-system corpus

Public water systems serving 500+ people (EPA SDWIS)

245 Higher than most more violations than 88% of 29,740 water systems

the national water-system corpus, bucketed by value

Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source EPA SDWIS · 2026-05-15

How many violations vs. how serious, among peer systems

Marlborough Water Works plotted against 29 peer public water systems (500+ people served), by total violation count (x) and the share of those violations that are health-based (y). The crosshair sits at this sample's own median on each axis. A high violation count does not automatically mean a serious record: most monitoring and reporting violations are minor, not health-based.

30 public water systems (500+ people served), EPA SDWIS current release.

How to read this

Each dot is one public water system; the highlighted dot is Marlborough Water Works. A system to the right has more recorded violations; a system higher up has a larger share of those violations classified health-based rather than monitoring or reporting.

Rare but serious: few violations, but most of them are health-based.
Frequent, mostly paperwork: many violations, but mostly monitoring or reporting, not health-based.
Clean record: below-median on both counts, the tinted corner.

View all 30 systems as a list

City of Ballinger: 372 violations, 85% health-based
Nooksack Valley Water Association: 16 violations, 31% health-based
Montgomery Co RWD 12: 7 violations, 29% health-based
Irvin Water District #6: 11 violations, 27% health-based
Ticonderoga WD: 47 violations, 26% health-based
Pine Valley Plantation: 37 violations, 24% health-based
McLouth, City Of: 29 violations, 17% health-based
Kipling Oaks 1: 25 violations, 16% health-based
South Deerfield Water Supply District: 96 violations, 16% health-based
Sunset Ridge Water District: 82 violations, 15% health-based
Orange Water Dept: 136 violations, 14% health-based
Mount Pleasant Water Sys #1: 167 violations, 11% health-based
Marlborough Water Works: 245 violations, 7% health-based (this system)
Lake Gibson Estates: 42 violations, 2% health-based
Benson Culinary Improvement District: 212 violations, 1% health-based
Conemaugh Twp Muni Auth: 567 violations, 1% health-based
Miccosukee Service Plaza: 0 violations, 0% health-based
Brazoria - Fort Bend Counties MUD 3: 0 violations, 0% health-based
Tanglewilde Thompson Place 600: 2 violations, 0% health-based
Center Water Co: 5 violations, 0% health-based
Spring Mills Elem School/Hvs: 9 violations, 0% health-based
Great Bend Industrial Park: 14 violations, 0% health-based
Glen Park Village: 19 violations, 0% health-based
Camp Is-Sho-Da: 22 violations, 0% health-based
Hamilton: 33 violations, 0% health-based
Town of Welaka: 54 violations, 0% health-based
Township of Blairstown Dpw: 61 violations, 0% health-based
McIntosh Water & Fire Pro Authority: 71 violations, 0% health-based
Clarkdale Municipal Water System: 114 violations, 0% health-based
Eureka Water Association: 273 violations, 0% health-based

Population served record for Marlborough Water Works

EPA SDWIS lists 750 people served and 300 connections for this PWS, confirm the service-area footprint on the federal report before comparing to municipal census totals.

EPA SDWIS · PWS NH1481010

Sources: EPA SDWIS

Nationwide peers

245 violations · 750 served: nearest cross-state SDWIS matches.

Cross-state systems with comparable violation load

Nearest cross-state community systems (500+ served) by total SDWIS violations on record.

4 peers

Cross-state systems with smaller service footprints

Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).

4 peers

What to do with Marlborough Water Works

Use this system's EPA-reported record as a starting filter, not a final verdict.

See how every tracked system in New Hampshire compares on the same EPA violation measures. New Hampshire systems
Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
Find and compare another public water system by name or PWSID. Search systems

EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Compiled by PlainWater, Drinking Water Quality Editorial Process · May 15, 2026

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.